SFI SYSTEM, Diagnostic DTC:P0100, P0102, P0103

DTC Code DTC Name
P0100 Mass or Volume Air Flow Circuit
P0102 Mass or Volume Air Flow Circuit Low Input
P0103 Mass or Volume Air Flow Circuit High Input

DESCRIPTION

The mass air flow meter sub-assembly is a sensor that measures the amount of air flowing through the throttle valve.

The ECM uses this information to determine the fuel injection time and to provide the appropriate air fuel ratio.

Inside the mass air flow meter sub-assembly, there is a heated platinum wire which is exposed to the flow of intake air.

By applying a specific electrical current to the wire, the ECM heats it to a given temperature. The flow of incoming air cools both the wire and an internal thermistor, affecting their resistance. To maintain a constant current value, the ECM varies the voltage applied to these components in the mass air flow meter sub-assembly. The voltage level is proportional to the air flow through the sensor, and the ECM uses it to calculate the intake air volume.

The circuit is constructed so that the platinum hot wire and the temperature sensor create a bridge circuit, and the power transistor is controlled so that the potentials of A and B remain equal to maintain the predetermined temperature.

Tech Tips

When any of these DTCs are set, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is calculated by the ECM, according to the engine speed and throttle valve position. Fail-safe mode continues until a pass condition is detected.

A01CC8FE05
DTC No. DTC Detection Condition Trouble Area
P0100

Open or short in mass air flow meter circuit for 3 seconds

(1 trip detection logic)

  • Open or short in mass air flow meter circuit


  • Mass air flow meter sub-assembly


  • ECM
P0102

Mass air flow meter voltage is less than 0.2 V for 3 seconds

(1 trip detection logic)

  • Open or short in mass air flow meter circuit


  • Mass air flow meter sub-assembly


  • ECM
P0103

Mass air flow meter voltage is more than 4.9 V for 3 seconds

(1 trip detection logic)

  • Open or short in mass air flow meter circuit


  • Mass air flow meter sub-assembly


  • ECM

Tech Tips

When any of these DTCs are set, check the air flow rate by entering the following menus on the intelligent tester: Powertrain / Engine / Data List / MAF.

Mass Air Flow Rate (gm/sec) Condition Malfunction
Approximately 0.0

  • Engine not running

  • 30 seconds after engine switch on (IG)

  • Open in mass air flow meter sub-assembly power source circuit


  • Open or short in VG circuit
0.49 or more

  • Engine not running

  • 30 seconds after engine switch on (IG)

  • Open in E2G circuit

Note


  • Perform the inspection with the vehicle indoors and on a level surface.

  • Perform the inspection of the mass air flow meter sub-assembly while it is installed to the air cleaner case (installed to the vehicle).

  • During the test, do not use an exhaust air duct on the exhaust tail pipe assembly.

WIRING DIAGRAM

A01CBCWE01

INSPECTION PROCEDURE

Tech Tips

Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (MAF)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) (do not run the engine).

    3. Enter the following menus: Powertrain / Engine / Data List / MAF.

    4. Wait 30 seconds, and read the values on the tester.

      Note


      • Perform the inspection with the vehicle indoors and on a level surface.

      • Perform the inspection of the mass air flow meter sub-assembly while it is installed to the air cleaner case (installed to the vehicle).

      • During the test, do not use an exhaust air duct on the exhaust tail pipe assembly.

      Result
      Mass Air Flow Rate (gm/sec) Proceed to
      0.0 A
      0.49 or more B
      More than 0.0 and less than 0.49 C

    B

    CHECK HARNESS AND CONNECTOR (SENSOR GROUND) Click here

    C

    CHECK FOR INTERMITTENT PROBLEMS Click here

    A

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE)


    1. A01CC1AE01

      Disconnect the mass air flow meter sub-assembly connector.

    2. Turn the engine switch on (IG).

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      D2-3 (+B) - Body ground Engine switch on (IG) 11 to 14 V

    4. Reconnect the mass air flow meter sub-assembly connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - EFI MAIN RELAY)

    OK

  3. INSPECT MASS AIR FLOW METER SUB-ASSEMBLY (VG VOLTAGE)


    1. A01CFDXE01

      Inspect the output voltage.


      1. Disconnect the mass air flow meter sub-assembly connector.

      2. Apply battery voltage across terminals +B and E2G.

      3. Connect the positive (+) tester probe to terminal VG, and the negative (-) tester probe to terminal E2G.

      4. Measure the voltage according to the value(s) in the table below.

        Standard Voltage
        Tester Connection Condition Specified Condition
        5 (VG) - 4 (E2G) Battery voltage applied across terminals +B and E2G 0.2 to 4.9 V

      5. Reconnect the mass air flow meter sub-assembly connector.


    NG

    REPLACE MASS AIR FLOW METER SUB-ASSEMBLY Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)


    1. Disconnect the mass air flow meter sub-assembly connector.

      A01CD9ZE01

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      D2-5 (VG) - D1-72 (VG) Always Below 1 Ω
      D2-4 (E2G) - D1-73 (E2G) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      D2-5 (VG) or D1-72 (VG) - Body ground Always 10 kΩ or higher

    4. Reconnect the mass air flow meter sub-assembly connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)

    OK

    REPLACE ECM Click here

  5. CHECK HARNESS AND CONNECTOR (SENSOR GROUND)


    1. A01CC1AE02

      Disconnect the mass air flow meter sub-assembly connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      D2-4 (E2G) - Body ground Always Below 1 Ω

    3. Reconnect the mass air flow meter sub-assembly connector.


    NG

    CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) Click here

    OK

    REPLACE MASS AIR FLOW METER SUB-ASSEMBLY Click here

  6. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)


    1. Disconnect the mass air flow meter sub-assembly connector.

      A01CD9ZE02

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      D2-4 (E2G) - D1-73 (E2G) Always Below 1 Ω

    4. Reconnect the mass air flow meter sub-assembly connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)

    OK

    REPLACE ECM Click here